The present invention relates to a valve for use in controlling the flow of fluids in general, and more particularly to a multiway switching valve for use in controlling the flow of gaseous fluids.
Valves of this general type are already known and in widespread use. Usually, a valve of this type includes a housing member which bounds a compartment, and a valve member which is mounted in the compartment for displacement between two terminal positions.
Under many circumstances, it is required that the control member of the valve of this type, that is, the valve member which may be elongated and mounted in the compartment of the housing member for longitudinal displacement, be securely retained in its terminal positions, in order to assure that the control portions thereof, such an annular lands, not be lifted or displaced with respect to the cooperating portions of the housing member owing to acceleration or deceleration forces, oscillations or the weight of the valve member. For this reason, it is necessary to provide an arrangement for arresting or retaining the valve member at least in one of the terminal positions thereof, especially when the valve is to be so mounted that the longitudinal axis thereof extends vertically or, generally speaking, at an angle to the horizontal or to a plane with respect to which all forces acting on the valve member act normal.
In order to achieve such an arresting action, it has already been proposed to use spring-biased balls which are movably mounted on one of the housing and valve members and are capable of entering corresponding recesses in the other of the housing and valve members. So, for instance, it has already been proposed to movably mount the balls in the housing member, and to form the recesses as annular grooves in the longitudinally slidable valve member. When this construction is resorted to, the balls are displaced against the spring forces acting thereon out of the respective annular groove when the displacement of the valve member from one to the other of its terminal position is initiated, as a result of which the arresting action of the balls is discontinued.
Arresting arrangements of this kind are very susceptible to malfunction during the operation of the valve. So, for instance, the balls or the springs can jam, or the arresting arrangement may become inoperative when dimensional changes take place in the valve during the operation thereof such as, for instance, as a result of deformation of sealing members or for similar reasons.
It has also been established that malfunctions occur especially when the respective valve is used in a circuit containing dry pressurized air inasmuch as the balls are not being lubricated under these circumstances and thus suffer a very considerable wear. This can result, especially in connection with valves having a high switching frequency, relatively rapidly in a complete deterioration of the balls or in a braking or other failure of the springs.